Boarding element for the boarding of iron-concrete plate-ceilings



Dec. 27, 1960 B. NovAK ET AL 2,965,951

BOARDING ELEMENT FOR THE BOARDING OF IRON-CONCRETE PLATE-CEILINGS f?Filed Oct. 15, 1958 2 Sheets-Sheet 1 v INVENTORJ I (fed/k6 /0V0A -.70:e/30/- Dec. 27, 1960 B. NovAK ETAL BOARDING ELEMENT FOR THE BOARDING OFIRON-CONCRETE PLATE-CEILINGS 2 Sheets-Sheet 2 Filed 001;. 15, 1958 wag/W United States Patent-O BOARDING ELEMENT FOR THE BOARDING OF IRON-CONCRETE PLATE-CEILINGS Bedi'ich Novak, 44 Hlavni, Uhersko, Czechoslovakia;

Josef Bartiisek, 1s Moskevska, Pardubice-Dukla, Czechoslovakia; andKarel Kerhart, 30 Pernerova, Pardubice, Czechoslovakia Filed Oct. 13,1958, Ser. No. 766,773

Claims priority, application Czechoslovakia May 29, 1958 7 Claims. (Cl.25-131.5)

The present invention relates to formboards for supporting elevatedreinforced concrete slabs forming ceilings and the like during thepouring and curing of such slabs.

The hitherto used supporting system for elevated reinforced concreteslabs consists usually of boards resting on horizontal wood carriers,which are supported by props of various types. The horizontal woodencarriers are replaced by metal carriers, lattice girders or plategirders, the length of which may be changed by telescoping or relativelyadjusting longitudinal members thereof. Wood is saved by the use of suchgirders, but the latter also have some disadvantages, in particular, thedifiiculty with which they are assembled, their great weight and highinitial cost.

The use of water-resistant plywood for the formboards and the method ofproducing reinforced concrete ceilings as disclosed in our applicationfor United States Letters Patent, Serial No. 769,946, filed October 27,1958, has led to the development of a formboard assembly with tiltablelattice girders according to the present invention.

By connecting a rigid plate of water-resistant plywood with a system ofsupporting lattice or truss girders extending at right angles to oneanother and disposed, during use, in planes perpendicular to that of theplywood plate, a structural member is produced which has a very smallweight but a high load carrying capacity.

The accompanying drawings show by way of example, a formboard assemblyembodying the invention.

In the drawings:

Fig. 1 is a bottom plan view of the formboard assembly, a Fig. 2 a crosssectional view along the line A-B of Fig. 3 is a cross sectional viewalong the line C-D of Fig. 1,

Fig. 4 is an elevation view of one of the lateral carriers included inthe assembly of Fig. 1,

Fig. 5 is an elevational view of one of the longitudinal or maincarriers of the assembly of Fig. 1,

Fig. 6 is a detail end view of an element included in the assembly ofFig. l, and

Fig. 7 is an elevational view of the element of Fig. 6.

The formboard assembly comprises a plate 20 formed of water-resistantplywood to which two main carriers 1, for example, in the form oflattice or truss girders, are permanently secured, and a plurality oftransverse carriers 2, also in the form of lattice girders and placed atright angles to the main carriers. The spacing of the transversecarriers 2 is chosen according to the load to be suggested by theformboard assembly.

The upper chords of the lattice girders forming the main carriers 1 andthe transverse carriers 2 are made of hollow steel tubes 3. The lowerchord and struts of each lattice girder are formed of steel rods 8 and4, respectively. The length of each of the carriers 1, 2 may be chan ed,and for this purpose, each of the carriers 1, 2 is divided into twoparts which may be connected by an 'ice ' extension piece 5 insertedbetween them. The connection of the piece 5 to the two. portions of thetop chord 3 is;

effected by thin-walled tubes 6 telescoping into the tubes 3 and securedby screws. The two portions of lower chord 8, subject to tensile stress,are connected to the corresponding part of extension piece 5 by means ofturnbuckle with left and right hand threads engaging correspondinglythreaded end portions on the parts of lower chord 8 and on extensionpiece 5.

Moreover, minor extension of the transverse carriers 2 may be efiectedby pulling out endtubes 10 which slidably telescope in the tubes 3 atboth ends of the transverse carriers 2.

The main carriers 1 and the lateral or transverse carriers 2 arepivotally secured to the underside of plywood plate 20 by means ofsleeves 13 slidable on the tube 3 of each carrier and secured to theplate 20 by screws. Thus, each carrier can pivot about its upper chordbetween an operative position in a vertical plane perpendicular to theplane of plate 20 and a stored position parallel to plate 20. Each ofthe transverse carriers 2 is secured in the operative vertical plane byhooks 11 (Fig. 4) pivotally mounted at the opposite ends of the bottomchord 8. The hooks 11 are movable to tilted-down positions where thehooks 11 engage the lower chords of the main car riers 1 between doublesleeves 12 (Figs. 5, 6 and 7) which are held in adjusted positions alongsuch lower chords corresponding to the spacing of the lateral carrier 2by means of set screws 12a.

The connection of all of the transverse carriers 2 to the two maincarriers 1 by means of the hooks 11 and the double sleeves 12 securesall carriers 1, 2 in vertical planes, thus increasing the rigidity ofthe assembly, with the result that the latter has a high load carryingcapacity, while having a very small weight.

The sleeves 13 make possible the turning of the main carriers 1 and thetransverse carriers 2 about the longitudinal axes of their upper chords3 so that each carrier can be tilted from the plane perpendicular to theformboard or plate 20 into a plane parallel to said plate, as shown infull lines on Figs. 2 and 3.

The formboard assembly described above may be supported by four props,placed below the ends of the main carriers 1. In order to facilitate theinstallation and removal of the described formboard assembly, the ply-.wood plate 20 is made shorter, by about 5 cm. in both directions, thanthe concrete ceiling slab to be cast. The

'gap along the periphery of the formboard or plate 20 is covered bysheet metal strips 15 which overlap the edge portions of plate 20 andhave depending flanges 16 along the outer periphery (Fig. 3) forabutment against the peripheral carrying structure of the building.

The strips 15 extending along the transverse and longitudinal ed es ofplate 20 are supported by tubes 17 and 10, respectively, which areslidable in the end portions of the tubes 3 forming the top chords ofthe main carriers 1 and transverse carriers 2. By sliding the end-tubes10 and 17 out, the overall dimensions of the formboard asse bl areincreased. The slidable tubes 10 and 17 are secured against inadvertentdisplacement by setscrews 18.

In operation, the carriers 1 and 2 are disposed in planes at rightangles to the formboard or plate 20 and secured in this position bybooks 11, whereupon the formboard assembly is lifted to the requiredheight and supported by props or oth r suitable means. The gaps betweenthe plate 20 and the Walls of the room or peripheral structure arecovered by the sheet metal strips 15 and the latter are secured bytightening the se screws 18 engageable with the slidable end-tubes 10and 17. Then the network of steel reinforcing rods is placed on theformboard 20 and the concrete is poured to form the desired slab. Afterthe concrete mixture has hardened, the formboardassembly of the ceilingslab is removed by releasing the props and lowering the whole formboardassembly down to lower the floor. The supporting carriers 1 and 2 arethen tilted to planes parallel to that of the plate 20. After thistilting operation the thickness of the formboard assembly is only about12 cm. The folded formboard assembly can then be pulled verticallythrough a gap left in the cast ceiling slab in the manner disclosed inour application Serial No. 769,946, identified more fully above,whereupon, the formboard assembly is disposed above the cast slab andcan be erected above the latter to serve as the formboard for thecasting of the next higher concrete slab.

Although a particular embodiment of this invention has been described indetail herein with reference to the accompanying drawings, it is to beunderstood that the invention is notlimited to that precise embodiment,and that various changes and modifications may be efiected thereinwithout departing from the scope or spirit of the invention, except asdefined in the appended claims.

We claim:

1. A formboard assembly comprising a flat plate, elongated carriersdisposed, with the assembly in working condition, below said flat plate,means pivotally connecting said carriers to said plate for swingingbetween operative positions, where the carriers lie in planesperpendicular to the pane of said flat plate and form a support for theplate, and stored positions, where the carriers lie substantially flatagainst the underside of said plate to reduce the thickness of theassembly to a minimum and to facilitate handling of the assembly, andmeans to releasably secure the carriers in their operative positions.

2. A formboard assembly comprising a flat plate presenting opposed sideedges and end edges, a pair of main carriers disposed below said flatplate and extending along and adjacent to said side edges, a pluralityof transverse carriers also disposed below said fiat plate and extendingbetween said main carriers at right angles to the latter, meanspivotally connecting said main and transverse carriers to said fiatplate for swinging between operative positions, where said carriers liein planes perpendicular to the plane of said flat plate, and foldedpositions, where said carriers are substantially fiat against theunderside of said fiat plate to reduce the thickness of the formboardassembly to a minimum, and cooperating latch means on said transversecarriers and on said main carriers releasably engageable when saidcarriers are in said operative positions to connect said main andtransverse carriers to each other and thereby retain said carriersinsaid operative positions for giving maximum load carrying support tosaid fiat plate.

3. A formboard assembly as in claim 2; wherein each of said carriers isin the form of a truss girder having elongated top and bottom chordmembers with connecting struts therebetweemand said means pivotallyconnecting said carriers to said plate engage said top chord member ofeach carrier so that the latter is swingable about the longitudinal axisof said top chord member.

4. A formboard assembly as in claim 3; wherein said latch means includeshook members pivotally connected to the opposite ends of said bottomchord member of each of said transverse carriers to swing relative tothe latter in the plane of the related transverse carrier and beingengageable with the bottom chord members of the adjacent main carriersto hold the latter in said operative positions thereof, and doublesleeves on the bottom chord member of each main carrier located toreceive the hook members at the adjacent ends of said transversecarriers between said double sleeves so as to hold said transversecarriers in said operative positions.

5. A formboard assembly as in claim 3; wherein the truss girder formingeach of said carriers includes two separable parts made up ofcorresponding portions of said top and bottom chord members and thestruts therebetween, and at least one extension piece secured to theadjacent ends of said portions of the top and bottom chord members forvarying the length of the related carrier.

6. A formboard assembly as in claim 3; wherein the top chord member ofeach of said carriers is constituted by a hollow tube; and furthercomprising extension tubes slidably telescoping in the end portions ofsaid hollow tube forming the top chord member of each carrier, and sheetmetal strips carried by the outer ends of said eittension tubes andslidably overlapping the edge portions of said fiat plate for adjustingthe overall dimensions of the formboard assembly.

7. In the formboard assembly according to claim 1, said elongatedcarriers being formed as lattice girders.

References Cited in the file of this patent UNITED STATES PATENTS2,297,952 Friberg Oct. 6, 1942 2,677,867 Aguirre-Gongalo et al. May 11,1954 2,687,193 Hinze Aug. 24, 1954 2,846,750 Anderson Aug. 12, 1958FOREIGN PATENTS 289,256 Germany Dec. 15, 1915

